Systems and methods for magnetized stent having growth-promoting properties

ABSTRACT

Embodiments relate to systems and methods for magnetized stent having growth-promoting properties. A stent assembly comprising a tubular elongated body having a magnetized region and a tissue nidus area is inserted beneath the orifice of a vascular aneurysm. The magnetic region can serve to attract and position both residual red blood cells and magnetically nano-ireated growth-promoting cells to the orifice area of the aneurysm. The outer circumference of the tubular elongated body can act as a floor or scaffold for regenerated smooth vascular muscle cells. In embodiments, the tissue nidus area can be provided on the exterior stent, while the magnetized region is provided on the interior stent, of a stent-in-stent structure. In embodiments, the exterior stent is made of biodegradable material which gradually dissolves or dissipates in situ.

REFERENCE TO RELATED APPLICATION

This patent application claims priority to U.S. Provisional ApplicationSer. No. 61/361,835, filed Jul. 6, 2010, which provisional applicationis incorporated in its entirety be reference herein.

GOVERNMENT INTEREST

This invention was made in part with Government support. The Governmenthas certain rights in the invention.

FIELD

The present teachings relate to medical devices, and more particularly,to a magnetized stent having growth-promoting properties.

BACKGROUND OF RELATED ART

A vascular aneurysm is a localized bulge or bubble that forms in thewall of a weakened blood vessel. If left untreated, a vascular aneurysmcontinues to expand until it ruptures, causing a hemorrhage, resultingin other complications or death. Vascular aneurisms can be caused by anynumber of factors that lead to a weakened blood vessel wall, includinghereditary factors, disease, or trauma. In the field of medicaltreatment of vascular aneurysms, various techniques have been attemptedto protect the weakened vessel wall from further deterioration andpossible rupture. Among those existing techniques include theapplication of an implanted clip or clamp, which provides a sealingforce sufficient to keep the bubbled or distended area of the vesselclosed. Another known technique is the use of endovascular coils ofcomparatively soft or springy wire-like material which are insertedthrough the orifice of the aneurysm, into the aneurysm sac itself.

Experience has shown that these techniques and others, unfortunately,suffer from certain drawbacks. In the case of aneurysm clipping, thisapproach necessitates an open craniotomy and the risks of woundinfection, inadvertent injury to adjacent vascular structures and damageto the functionally eloquent nearby areas of the brain. In the use of animplanted coil which is performed using endovascular surgery, aminimally invasive approach, the coils themselves may be prone tounraveling and migration inside the parent artery of the aneurysm, whichcan require further surgery to re-position the coils or to perform othercorrective actions. Although durability of treatment is provided byaneurysm clipping since the defect across the aneurysm neck or itsorifice is drawn together by the clip re-establishing the weakened bloodvessel wall, the attendant risks of open surgery for this proceduremakes this the less favorable choice when compared to a minimallyinvasive procedure. In existing treatment using endovascular methods forcoiling aneurysms, there is also minimal or no tissue re-growth acrossthe orifice, which provides little or no relief in terms of fluidbuildup or pressure inside the aneurysm itself. It may be desirable toprovide systems and methods for a magnetized stent havinggrowth-promoting properties, which, among other advantages, may allowsufficient structural support and induction of tissue growth toeffectively re-seal the orifice of the aneurysm, relieving fluid flowand pressure in the aneurysm and significantly reducing or eliminatingthe possibility of a later rupture of the damaged vessel.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentteachings and together with the description, serve to explain theprinciples of the present teachings. In the figures:

FIG. 1A illustrates an overall stent assembly for a magnetized stenthaving growth-promoting properties, according to various embodiments;

FIG. 1B illustrates a side view of a circumferential wall of a tubularelongated body, according to various embodiments;

FIG. 2A illustrates an overall stent assembly for a magnetized stenthaving growth-promoting properties, according to further variousembodiments; and

FIGS. 2B-2D illustrate various side or inclined views of thecircumferential walls of tubular elements in a stent assembly, accordingto the further various embodiment shown in FIG. 2A.

SUMMARY

Embodiments of the present teachings relate to systems and methods formagnetized stent having growth-promoting properties. More particularly,embodiments relate to a novel stent assembly and associated techniquesincluding the use of a stent structure having a magnetized regionfocused on or directed to the orifice of a vascular aneurysm or otherblood vessel defect from one side of the stent circumference. Theresulting local magnetic field can serve to attract cells comprisingmagnetic nanoparticles or magnetic or paramagnetic components of tissueor blood, such as methehemoglobin-bearing red blood cells or otherelements of blood, to the area of the orifice. The area of the outercircumference of the stent assembly facing the orifice of the aneurysmcan also have a tissue nidus area that can be treated or impregnatedwith a tissue growth medium and/or smooth muscle cells. While thetubular mesh body of the stent can provide a rigid structural support tomaintain the integrity of the injured blood vessel, the local magnetizedregion can preferentially attract cells and other factors havingmagnetic properties, which when concentrated in the same area as thetissue nidus area, can promote or induce the growth of tissue, such asvessel lining or muscle layers (e.g. tunica intima, tunica media, ortunica adventitia), particularly across the aneurysm orifice or otherblood vessel defect. According to aspects, the magnetized stent assemblyhaving growth promotion properties and related techniques can therebyachieve partial or total sealing of vessel aneurysms, while requiringonly a correct initial surgical placement and with little or no risk ofrequired reparative procedures later.

These and other embodiments described herein address the various notedshortcomings in known stent technology, and provide a physician,patient, or others with an enhanced stent design providing surgical andclinical effectiveness in reinforcing and healing vascular aneurysmsand/or other injuries or defects.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments of thepresent teachings, which are illustrated in the accompanying drawings.Where possible the same reference numbers will be used throughout thedrawings to refer to the same or like parts.

FIG. 1A illustrates a stent assembly 100 according to aspects of thepresent teachings. In embodiments as shown, the stent assembly 100 cancomprise a tubular elongated body 102. In aspects, the tubular elongatedbody 102 can be or include a patterned mesh or lattice, for examplearranged in a sinusoidal, diamond, square, circular, or other pattern.In embodiments, the tubular elongated body 102 can be made of acompressible and/or expandable material or materials. In aspects, thatmaterial can be or include a metal or metals, such as stainless steel ornitinol. In aspects, nitinol may be preferred due to its resistance todeformation in a hemodynamic environment. In embodiments, that materialcan also or instead include non-metallic materials, such as plasticmaterials, biodegradable materials, or others. The tubular elongatedbody 102 can be fashioned to be of proportion and type to be insertedinto a blood vessel or other lumen or tissue using a catheter deliverysystem, which, as understood by persons skilled in the art, cangenerally involve the mechanical transport and insertion of the stentassembly 100 using a narrow, hollow, conductive tube or microcatheter122 operated by a surgeon or other clinician.

In aspects as shown, the tubular elongated body 102 can comprise or canhave associated with it a magnetized region 104. In aspects, themagnetized region 104 can be or include a permanently magnetized area,region, and/or section of the tubular elongated body 102 intended to begenerally positioned beneath, under, and/or otherwise in contact with,proximal, or adjacent to an aneurysm orifice or other area of thesubject tissue to which treatment is to be directed. In aspects, towardthat end, the magnetized region 104 can be provided in a region of thetubular elongated body 102 extending in a partial circumferential regionof the tubular elongated body 102, intended to correspond to or overlapwith the aneurysm orifice or other area of tissue targeted fortreatment. In aspects, the magnetized region 104 can be impressed onlyin an outward-facing region of the tubular elongated body 102, so as todirect a magnetic field toward the aneurysm orifice or other area oftissue targeted for treatment, but not in the interior lumen of thetubular elongated body. In aspects, the partial circumferential regionof the tubular elongated body 102 which can be permanently magnetizedcan include any desired radial cross-section of the tubular elongatedbody 102, such as, for example, one-half of the circumference of thetubular elongated body 102, or less. The permanent magnetization of thedesired region of the tubular elongated body 102 can be impressed uponthe tubular elongated body 102 by techniques known to persons skilled inthe art, such as by using the application of electric and/or magneticfields to the desired magnetized region 104. Magnetization of themagnetized region 104 can be produced by exposing or contacting thedesired magnetized region 104 with existing magnetic materials,including but not limited to exposure to neodymium magnets. In these orother embodiments, to improve the magnetic properties of the magnetizedregion 104, the tubular elongated body 102 can be coated with a metal,including but not limited to nickel.

Magnetization of the magnetized region 104 can also or instead beproduced by exposure of the magnetized region 104 to magnetizednanoparticles to confer magnetic polarization. In such aspects,nanoparticles can be synthesized on the surface of the tubular elongatedbody with heavy-ion beam irradiation. The conferring of a magneticpolarity in the magnetized region 104 can cause the outer surface ofthat region to have localized, magnetic properties, the ability topromote tissue growth, and improved biocompatibility. Magnetization ofthe magnetized region 104 can also or instead be produced using othermaterials or techniques.

In embodiments as shown in FIG. 1A, the tissue to which treatment is tobe directed using the stent assembly 100 can be or include an artery200, such as a human artery located in the heart, the brain, and/orother organs or body areas. The artery 200 can comprise layers ofendothelial or muscle cells including a tunica media 210, a tunicsintima 208, and a tunics adventitia 206. In aspects, the defect, injury,or condition to which treatment using the stent assembly 100 is to beconducted can be or include an aneurysm 202 including a cavity 212(i.e., an aneurysm sac) and an orifice 204 formed in the artery 200,creating an outwardly bulging or extended bubble or deformation in theartery 200. It may be noted that in aspects, the aneurysm 202 can beformed or created by traumatic events such as blunt trauma, penetratingbrain injury, explosive shock, strokes, and/or other causes, includingthose that can be produced in wartime environments, or as a result ofother scenarios. In aspects, the typical size or diameter of the cavity212 may be on the order of 3 mm, although larger and smaller sizes mayalso be presented. The typical size or diameter of the orifice 204 canbe on the order of one-third of the size of the cavity 212, orapproximately 1 mm, although larger or smaller diameters may bepresented.

In aspects as likewise shown, the stent assembly 100 can also comprise atissue nidus area 106. As used herein, the “tissue nidus area 106”refers to an area of the tubular elongated body 102 of the stentassembly 100 that promotes the growth of tissue, such as the tissue of ablood vessel, including, but not limited to, the tunica intima 208,tunica media 210. and/or tunica adventitia 206. Among the layers of thevessel wall of artery 200, it is the smooth muscle layer, or tunicamedia 210, that is missing in the area of aneurysm development. Thesmooth muscle layer or tunica media 210 provides the wall of bloodvessel 200 with the resilience needed to maintain its integrity, despitevariations in blood pressure buildup. Reconstruction of the tunica media210 across the orifice 204 therefore promotes durability of treatment.

The tissue nidus area 106 can, if desired, be treated withgrowth-promoting medium, tissue, cells, and/or other material. Inaspects, the tissue nidus area 106 can, for instance, include smoothmuscle cells, including mammalian cells such as porcine coronary smoothmuscle cells or histocompatible human smooth muscle cells. Porcinegrafts have been used for human vascular grafts without showing signs ofrejection. The growth-promoting material in the tissue nidus area 106can likewise include material such as peroxisome proliferators activatedreceptor- gamma (PPAR-gamma), and/or other media or materials. Inaspects, the growth-promoting medium, tissue, cells, and/or othermaterial can be applied, adhered, injected, or attached in or to thetubular elongated body 102 as a paste, a wafer, and/or tissue fragments.In embodiments, the tissue nidus area 106 can comprise mammalian smoothmuscle cells in which magnetic nanoparticles have been introduced and/orabsorbed. In embodiments, the tissue nidus area 106 can be provided onan outer surface of the tubular elongated body 102, and/or can beinterspersed in the mechanical cells or other interstitial areas betweenthe skeletal mesh of the tubular elongated body 102.

As further illustrated in FIG. 1B, for example, the magnetized region104 and tissue nidus area 106 can be arranged or configured to partiallyor totally overlap, with for instance the tissue nidus area 106 beingoriented directly over and substantially or completely overlapping withthe magnetized region 104. Other configurations or relationships betweenthe position of the magnetized region 104 and tissue nidus area 106 canbe used.

According to aspects, the stent assembly 100 can be inserted into ablood vessel or other tissue, and positioned to orient the magnetizedregion 104 and tissue nidus area 106 underneath the orifice 204. Inaspects, the surgeon or other physician can introduce the stent assembly100 into a blood vessel using a catheter-based or other delivery system116, as understood by persons skilled in the art. The stent assembly 100can be directed longitudinally through the blood vessel or other tissueto reach the area of the aneurysm 202, at which point the surgeon orother physician can rotate the stent assembly 100 to cause themagnetized region 104 and tissue nidus area 106 to be aligned orpositioned underneath the orifice 204. In aspects, the stent assembly100 can be secured into place in this position by releasing amicrocatheter 122 located in the tip of the delivery system 116,allowing the stent assembly 100 to expand slightly into place due to thenatural spring action of the mesh material of the tubular elongated body102. In aspects, the positioning action can be aided by the use ofendoscopic imaging systems, such as a camera located in the stentdelivery system, by tomographic imaging devices, and/or by other imagingmeans. After insertion and positioning of the stent assembly 100underneath the orifice 204 of the aneurysm 202, in aspects, smoothmuscle cells laden with magnetic nanoparticles can be delivered via themicrocatheter 122 or other channel or device within the aneurysm cavity212, which encapsulated smooth muscle cells can react with the poroussurface of the magnetized region 104 now covering the base of theaneurysm 202.

Upon proper orientation and placement of the stent assembly 100underneath the orifice 204 of the aneurysm 202, the therapeutic actionof the stent assembly 100 can thus be effected upon the aneurysm 202through a combination of mechanical, magnetic, and/or bioactive effectsto induce or promote the growth of healing tissue over the orifice 204and other areas of the aneurysm 202. More particularly, in aspects, thepresence of the magnetized region 104 can attract magnetic orparamagnetic constituents of blood or plasma in the area of the orifice204, due to the short-range magnetic field established by the magnetizedregion 104. Residual blood left within the aneurysm cavity 212 arerendered paramagnetic due to disuse, and thus will adhere to themagnetized region 104 acting as a floor of the aneurysm orifice 204. Thehemoglobin component in old circulating blood cells changes tomethemoglobin as its ferrous ion changes to ferric, thus renderingresidual red blood cells paramagnetic.

In embodiments, the presence of magnetic or paramagnetic constituentscan be enhanced or promoted by the injection of magnetic nanoparticlesinto the cavity 212 through microcatheter 122 or other means, such asother channels of the delivery system 116, or others. In embodiments,the magnetic nanoparticles can become attached to or absorbed into bloodcells, muscle cells, or other tissue or material, and thus bemagnetically drawn to the area of the orifice 204. The attraction ofmagnetically treated or untreated hemoglobin molecules to the orifice204 can, for example, promote the growth of vascular muscle or othertissue in the area of the orifice 204. In aspects, the outer surface ofthe tubular elongated body 102 can act as a mechanical support orstructure upon which tissue growth can take place.

In addition to and combining with the growth-inducing properties of themagnetized region 104, the presence of the tissue nidus area 106 canfurther promote the growth of muscle and/or other tissue across theorifice 204. The tissue nidus area 106 can serve as a substrate for theestablishment and growth of tissue across the orifice 204, providingcells, nutrients, and/or other growth factors to promote the developmentof replacement tissue across the orifice 204. In aspects, the presenceof a growth-promoting medium in the interstitial spaces or otherportions of the tubular elongated body 102 can likewise reduce theeffective porosity of the stent assembly 100 across the boundary of theorifice 204, reducing fluid pressure in the aneurysm 202 and furtherhelping to maintain the integrity of the affected vessel area againstdeterioration. In further embodiments, the various sections of the stentassembly 100 can be formed to have patterned meshes or lattices ofdifferent sizes, and thus, different porosities. For instance, thetissue nidus area 106 can be formed to have a smaller patterned mesh orlattice size than other sections of the stent assembly 100, and hence,have reduced porosity compared to regions of the tubular elongated body102 located outside the tissue nidus area 106.

According to aspects, after implantation of the stent assembly 100across the orifice 204, over time the combined structural, magnetic,and/or bioactive effects of the stent assembly 100 can cause replacementmuscle and/or other tissue to grow across the complete diameter of theorifice 204 of the aneurysm 202. In one embodiment, the stent assemblypromotes the growth of the tunics media 210 across the orifice 204.After sufficient time, the orifice 204 can become completely covered orsealed by that replacement tissue, cutting off any blood flow or leakageinto the cavity 212 and significantly reducing or eliminating risks tothe patient from the presence of the aneurysm 202.

FIG. 2A illustrates a magnetized stent assembly 150 havinggrowth-promoting properties, according to further embodiments. Inembodiments as shown, the stent assembly 150 can comprise a firsttubular elongated body (or an outer tubular mesh 108), inside of which asecond tubular elongated body (or an inner tubular mesh 110) ispositioned or mounted. While inner tubular mesh 110 is illustrated asbeing of smaller size than outer tubular mesh 108 for ease ofillustration, it should be noted that in embodiments, outer tubular mesh108 can be smaller than inner tubular mesh 110, or in furtherembodiments the two meshes, outer tubular mesh 108 and inner tubularmesh 110, can be of the same size.

In aspects shown for instance in FIG. 2D, the outer tubular mesh 108 cancomprise a tissue nidus area 114, which can be formed and configured ina similar manner to the same or similar tissue nidus areas describedabove in connection with embodiments illustrated in FIG. 1A. It may benoted that in embodiments, the outer tubular mesh 108 can be made of abiodegradable material 118, such as polyglycolic acid material orpolylactic acid material, to permit the reabsorption of the outertubular mesh 108 within the vessel area under treatment. In aspects,other materials, such as other materials used in biodegradable suturesor grafts, can also be used to form the outer tubular mesh.

In aspects, the inner tubular mesh 110 can comprise a stent assembly,such as a skeletal wire-mesh stent made of stainless steel, nitinol, orother material, as described above in connection with embodimentsillustrated in FIG. 1A. In aspects for instance also shown in FIG. 2D,the inner tubular mesh 110 can in aspects be provided with a magnetizedregion 112, which can be formed and configured in a similar manner tothe same or similar magnetized region described above in connection withFIG. 1A. In aspects, and as for instance shown in FIG. 2B, the innertubular mesh 110 can comprise a tubular mesh structure which is insertedconcentrically inside of the outer tubular mesh 108, for instance, afterplacement of outer tubular mesh 108 inside artery 200, duringmanufacture, during preparation before any surgical procedure, and/or atother times.

In aspects, and as for instance shown in FIG. 2C, the outer tubular mesh108 and inner tubular mesh 110 can be made with different mesh orlattice patterns. In aspects, the two lattices of the outer tubular mesh108 and inner tubular mesh 110 can be structurally designed to be atcross-lattices to, and/or to otherwise complement, one another. The twolattices can thereby in aspects grip or lock in place together. Thosepatterns can be or include a square repeating pattern or shape for theouter tubular mesh 108 and a diamond-shaped repeating pattern or shapefor the inner tubular mesh 110, as shown. It will however be appreciatedthat additional or different patterns or shapes can be used for each ofthe outer tubular mesh 108 and inner tubular mesh 110.

According to aspects, the stent assembly 100 shown in FIG. 2A can beinserted in similar fashion to that described for embodiments noted inconnection with FIG. 1A above, which is to say, generally involvesplacing the stent assembly 100 underneath the orifice 204. In aspects,the outer tubular mesh 108 can for instance be first inserted intoartery 200 with magnetized region 112 positioned underneath orifice 204using balloon catheter 120 or other device, followed by insertion ofinner tubular mesh 110 inside of the outer tubular mesh 108 using theballoon catheter 120 or other device with magnetized region 112positioned underneath and/or in partial or total alignment with thetissue nidus area 114, to form a stent-in-stent assembly. In aspects,the outer tubular mesh 108 and inner tubular mesh 110 can be inserted inother orders and/or configurations, for instance, by inserting innertubular mesh 110 first followed by insertion of outer tubular mesh 108second, inside or outside of the inner tubular mesh 110, to form otherconfigurations or types of stent-in-stent assembly.

In aspects, positioning and locking outer tubular mesh 108 and innertubular mesh 110 in place in such a manner can serve to situate orposition the magnetized region 112 and tissue nidus area 114 in theorifice 204 and to direct the magnetic field, structural support, and/orbioactive effects of the stent assembly 100 to the orifice 204 of theaneurysm 202 formed in the subject vessel. It may be noted that inembodiments, the inner tubular mesh 110 can be formed without anyspecial growth-medium, porosity, and/or other features. In aspects, theinner tubular mesh 110 can comprise a conventional and/or commerciallyavailable tubular body, which can be selectively magnetized in themagnetized region 112 and act as a support to outer tubular mesh 108. Inembodiments, however, if desired, the inner tubular mesh 110 can also beformed with growth-medium or other features of its own, to augment thegrowth-promoting effects or benefits of the outer tubular mesh 108. Itshould be noted that in aspects, the surgical positioning of the stentassembly 150 shown in FIG. 2A does not require recourse to the use of amicrocatheter 122 or other instrument inserted inside the aneurysmcavity 212 or sac to deliver magnetized cells or micelles.

It should be noted that while embodiments are described above inconnection with the surgical treatment of an aneurysm 202 and associatedfeatures, the stent assembly 100 of the invention can be applied and/oradapted to other injuries, diseases, or defects. For instance, in thecase of a heart containing a congenital defect such as a patent foramenovale (PFO), the invention may be adapted to provide a one-facedmagnetic disc on one side of the heart while providing a second(paramagnetic) disc on the other side of the heart, positioned aroundthe defect opening. Other organs and/or conditions can be treated withmagnetic, structural, and/or growth-promoting effects according to thepresent teachings.

The foregoing description is illustrative, and variations inconfiguration and implementation may occur to persons skilled in the artFor example, while embodiments have been described in which the tubularelongated body 102 of the stent assembly 100 is illustrated as having auniform diameter, in embodiments, the tubular elongated body 102 can beformed to have varying diameters along its length. For further example,while embodiments have been described in which the stent assembly 100contains one magnetized region 104 and one tissue nidus area 106, inembodiments, the stent assembly 100 can be formed to contain more thanone magnetized region 104 and/or more than one tissue nidus area 106.For yet further example, while stent-in-stent embodiments have beendescribed in which one inner tubular mesh is nested within an outertubular mesh, in embodiments, three or more tubular meshes or otherstructures can be nested in stent-in-stent fashion. For still furtherexample, while embodiments have been described in which a stent assemblycan be fashioned using a stent-in-stent configuration in which one stentcan be made of metal material while the other stent can be made ofbiodegradable material, in embodiments, a stent assembly can be made inusing a unitary configuration using a hybrid metal and biodegradableconstruction. Other elements or resources described as singular orintegrated can in embodiments be plural or distributed, and elements orresources described as multiple or distributed can in embodiments becombined. The scope of the present teachings is accordingly intended tobe limited only by the following claims.

What is claimed is:
 1. A stent assembly, comprising: a tubular elongatedbody having an inner and outer surface, wherein the tubular elongatedbody comprises: a tissue nidus area comprising growth-promoting materialpositionable underneath an orifice of a vascular aneurysm, wherein thetissue nidus area is provided on the outer surface of the tubularelongated body and comprises an area of the tubular elongated bodycoated with muscle cells comprising magnetic nanoparticles; and amagnetized region, alignable with the tissue nidus area, for applying amagnetic field to the orifice of the vascular aneurysm to promote tissuegrowth on the tissue nidus area and across the orifice.
 2. The stentassembly of claim 1, wherein the tissue nidus area and the magnetizedregion are located on the outer surface of the tubular elongated body.3. The stent assembly of claim 2, wherein the magnetized regioncomprises a magnetized region on the outer surface of the tubularelongated body extending over a portion of the circumference of thetubular elongated body.
 4. The stent assembly of claim 3, wherein theportion of the circumference comprises at most one half of thecircumference.
 5. The stent assembly of claim 4, wherein the portion ofthe circumference comprises a circumscribed area corresponding to thatof the orifice.
 6. The stent assembly of claim 1, in which the tubularelongated body comprises an expandable tubular metal mesh.
 7. The stentassembly of claim 6, wherein the tubular metal mesh comprises at leastone of nitinol or stainless steel.
 8. The stent assembly of claim 1,wherein the magnetized region comprises magnetized nanoparticles.
 9. Thestent assembly of claim 1, wherein the tissue nidus area is located onthe outer surface of the tubular elongated body and the magnetizedregion is located on an inner tubular mesh concentrically mounted insidethe tubular elongated body.
 10. The stent assembly of claim 9, whereinthe tubular elongated body is made of a biodegradable material.
 11. Thestent assembly of claim 1, wherein the tissue nidus area and themagnetized region at least partially overlap.
 12. The stent assembly ofclaim 11, wherein the tissue nidus area and the magnetized region arecoextensive.
 13. The stent assembly of claim 1, wherein the muscle cellscomprise mammalian vascular smooth muscle cells.
 14. The stent assemblyof claim 13, wherein the mammalian vascular smooth muscle cells comprisehuman or porcine vascular smooth muscle cells.
 15. A method of treatinga vascular aneurysm in a subject, comprising: introducing the stentassembly of claim 1 into a blood vessel of the subject, wherein theblood vessel comprises the vascular aneurysm; and positioning the tissuenidus area and the magnetized region underneath an orifice of the bloodvessel to promote tissue growth across the orifice of the vascularaneurysm.
 16. The method of claim 15, further comprising introducingcells comprising magnetized nanoparticles into the vascular aneurysm.